Synthesis and X-ray characterization of 15- and 16-vertex closo-carboranes

Abstract

Carboranes are a class of carbon-boron molecular clusters with three-dimensional aromaticity, and inherent robustness. These endowments enable carboranes as valuable building blocks for applications ranging from functional materials to pharmaceuticals. Thus, the chemistry of carboranes has received tremendous research interest, and significant progress has been made in the past decades. However, many attempts to the synthesis of carboranes with more than 14 vertices had been unsuccessful since the report of a 14-vertex carborane in 2005. The question arises as to whether these long sought-after molecules exist. We describe in this article the synthesis and structural characterization of 15- and 16-vertex closo-carboranes as well as 16-vertex ruthenacarborane. Such a success relies on the introduction of silyl groups to both cage carbons, stabilizing the corresponding nido-carborane dianions and promoting the capitation reaction with HBBr2·SMe2. This work would shed some light on the preparation of carboranes with 17 vertices or more, and open the door for studying supercarborane chemistry.

Electronic Structure of Superoxidized Radical Cationic Dodecaborate-Based Clusters

“…Substituents with varying electronics surrounding the cage significantly affect the redox potential of the 0/•+ couple and, as a result, the properties of the radical cation clusters. As the materials chemistry of boron clusters is gaining a renewed interest in the community, − this work serves as another benchmark for new boron cluster systems with tunable redox-active properties.…”

Functionalization of o-carboranes via carboryne intermediates

“…They exhibit three-dimensional aromaticity conjugated by s bonds, and have a spherical geometry with inherent robustness. 1,2 These features have made carboranes invaluable building blocks for application in functional materials, [3][4][5][6][7][8][9][10] medicine/pharmaceuticals, [11][12][13][14][15] and coordination/organometallic chemistry [16][17][18][19][20] in recent years by a wide recognition of their unique electronic properties, geometry, and extraordinary versatility. 1,21 Among the three structural isomers (o-, m-, and p-carborane), o-carborane (1,2-C 2 B 10 H 12 ) is the most widely investigated due to its commercial accessibility.…”

Regioselectivity of Pd-catalyzedo-carborane arylation: a theoretical view

“…Carboranes are a class of boron clusters in which one or more B-H vertices are replaced by C-H units. [1][2][3] Since the 1960s, the precursor works and the definition for this kind of compound have been reported. 4 Meanwhile, the icosahedral carboranes as the most important carboranes have attracted widespread attention due to their many attractive properties, such as unique thermal and chemical stability, 5,6 enriched boron content, [7][8][9] three-dimensional aromaticity 10,11 and so on.…”